A) Field of the Invention
The present invention relates to an optical disk recording method and apparatus for recording data in an optical disk such as CD-R, CD-RW, CD-WO, MD and DVD, and more particularly to an optical disk recording method and apparatus for properly recording data in an optical disk in a manner matching the environments and the like of an optical disk drive.
B) Description of the Related Art
An optical disk recording apparatus for recording data in an optical disk such as CD-R and CD-RW performs an optimum power control (OPC) to obtain beforehand an optimum optical power of the optical disk. OPC obtains an optimum optical power in accordance with the characteristics of a storage medium, the characteristics of a laser diode (LD), a variation of the optical power and the like in order to record data at the optimum optical power. OPC is a record power control method in which trial write of test data is performed in a power calibration area (PCA) of the innermost circumference of the optical disk by stepwise changing an LD record power at a predetermined recording velocity (linear velocity). β (asymmetry) of a signal reproduced from the test data is evaluated and the record power which realizes the best β is determined as the optimum record power at the record velocity used. Japanese Patent Application Laid-Open Nos. Hei10-105972 and Hei11-273073 disclose an optical disk recording method in which test data is recorded in a plurality of areas along a circumferential direction of an optical disk and the optical record powers obtained in respective areas are averaged in order to suppress the influence of sensitivity variations.
An optical disk recording apparatus for recording data in an optical disk at a constant linear velocity can shorten a record time by recording data at a high velocity such as 2×, 4× and 8×relative to a reproducing velocity (standard velocity). An optical disk proper record velocity judgement method is also proposed (Japanese Patent Application Laid-Open No. 2001-67672) in which OPC is performed by changing the record velocity and record power, recorded data is reproduced, the qualities of reproduced signals are measured, the highest velocity corresponding to the record power realizing the reproduced signal quality in a predetermined allowance range is displayed as a recommended velocity, and a user sets this record velocity for the actual record of data.
With the above-described conventional optical disk recording methods, the optimum (highest) record velocity is determined by OPC prior to the actual data record. During the actual data record, data may become missing if the load of a host computer becomes heavy and the data transfer rate lowers, if the record laser power increases near to the maximum value because of a change in ambient environments.